Saudi billionaire Prince Alwaleed bin Talal is now the proud owner of more than 5 percent of Twitter shares, worth about $1 billion.

That investment could be seen as a show of confidence from the prince, who previously said he didn't think Twitter co-founder Jack Dorsey should be named CEO. Dorsey is also chief executive of Square, the mobile payments company he co-founded, which is expected to go public later this year.

Alwaleed now owns about 30 million shares, and his investment arm, Kingdom Holding Company, has 5 million shares. That combined holding makes him Twitter's second-largest shareholder, after co-founder Ev Williams, who owns almost 7 percent.

The prince, who had acquired a 3 percent stake in 2011, spent about $50 million to boost his stake, according to a filing Wednesday. His latest investment is notable for two reasons. First, he is or has been a major investor in Apple, Citigroup, AOL and News Corp, among others. Second, Alwaleed in June told the Financial Times that he did not support naming Jack Dorsey, then Twitter's interim chief, as the new CEO.

"Jack has another company called Square which requires a lot of attention and a full-time job round there," he told the paper in June. "I believe and trust that Jack Dorsey is there on a temporary basis," he said.

Twitter on Monday said Dorsey, who was the company's first CEO until his ouster in 2008, is now the company's full-time chief executive.